function StrSIDToName(const StrSID: Widestring; var Name: WideString; var SIDType: DWORD): DWORD;
var
  SID : PSID;
  Buffer : PWideChar;
  NameLen, TempLen : Cardinal;
  err : Boolean;
begin
  SID := nil;
  err := ConvertStringSIDToSID(PWideChar(StrSID), SID);
  if err then
  begin
    NameLen := 0;
    TempLen := 0;
    if LookupAccountSidW(nil, SID, nil, NameLen, nil, TempLen, SIDType) then
    begin
      GetMem(Buffer, NameLen);
      try
        err := LookupAccountSidW(nil, SID, Buffer, NameLen, nil, TempLen, SIDType);
        if err then
        begin
          SetString(Name, Buffer, Namelen);
          SetLastError(0);
        end;
      finally
        FreeMem(Buffer);
      end;
    end;
  end;
  if Assigned(SID) then
    LocalFree(Cardinal(SID));
  result := GetLastError;
end;